Evaluation of the association between predictive factors and the development of immune‐related adverse events and prognostic factors for chemoimmunotherapy in patients with non‐small cell lung cancer: A multicenter retrospective study

Abstract Introduction Chemoimmunotherapy is widely used as the first‐line management of advanced non‐small cell lung cancer (NSCLC) in clinical settings. However, predictive factors associated with the development of immune‐related adverse events (irAEs) and prognostic factors for NSCLC patients undergoing chemoimmunotherapy remains largely unexplored. Therefore, in this study, we aimed to evaluate predictive factors for irAE development and prognostic factors associated with chemoimmunotherapy in NSCLC patients. Methods This study enrolled 199 patients with advanced and recurrent NSCLC who underwent chemoimmunotherapy across eight institutions in Nagano prefecture from December 2018 to January 2023. We examined predictive factors associated with irAE development and prognostic factors associated with overall survival (OS). Results Among the patients, 106 experienced irAEs, while 93 patients did not. A total of 44 (22.1%) patients developed multiple irAEs. High serum albumin levels (Alb >3.5 g/dL) emerged as an independent predictive factor associated with irAE development in logistic regression analysis (odds ratio; 2.35, 95% confidence interval 1.27–4.34, p = 0.007). Furthermore, the development of multiple irAEs (p = 0.016), lower lactate dehydrogenase level (<223 U/L, p = 0.002), and decreased neutrophil‐to‐lymphocyte ratio (<3, p = 0.049) were identified as independent favorable prognostic factors associated with OS in multivariate Cox hazard analyses. Conclusion The study results suggest that high serum Alb is a predictive factor for irAE development and that the presence of multiple irAEs is a favorable prognostic indicator for NSCLC patients undergoing chemoimmunotherapy.


| INTRODUCTION
The development and approval of immune checkpoint inhibitors (ICIs) for advanced non-small cell lung cancer (NSCLC) have significantly improved patient prognosis.2][3][4][5][6][7] ICIs enhance immune system function, leading to clinical benefits, but immune checkpoint blockade can induce inflammatory side effects known as immune-related adverse events (irAEs).These irAEs can affect various organs or tissues, with the skin, colon, endocrine organs, liver, and lungs being commonly affected.Although less frequent, irAEs in other organs, such as neurological disorders and myocarditis, can be severe, even fatal. 8The incidence of irAEs varies depending on the type of ICI used and whether it is combined with cytotoxic anticancer agents.In trials such as CheckMate 017 9 and CheckMate 057, 10 irAEs occurred in 58%-69% of patients receiving nivolumab, with 7%-10% being grade 3 or 4. Combination therapy with nivolumab and ipilimumab has been associated with incidences of irAE, with CheckMate 227 reporting any irAE in 76.7% of patients and 32.8% being grade 3 or 4. 11 In trials such as IMpower130, IMpower132, and IMpower150, chemoimmunotherapy with atezolizumab resulted in irAE incidence of ranging 45%-60%. 123][14] Moreover, Shimozaki et al. demonstrated that the overall survival (OS) of patients with multiple irAEs was significantly longer than that of patients with a single irAE. 14Appropriate management of irAEs is crucial to optimize treatment outcomes, necessitating the identification of patients susceptible to irAEs.6][17][18][19] However, limited data exist regarding chemoimmunotherapy.Fujimoto et al. suggested squamous cell carcinoma, anti-PD-1 plus anti-CTLA-4 regimens, and NLR <3 as potential predictive factors for irAEs during chemoimmunotherapy induction with platinum agents in patients with NSCLC. 20evertheless, further clinical evidence is warranted.Thus, this study aimed to evaluate predictive factors for irAE development and prognostic factors associated with chemoimmunotherapy in NSCLC patients.

| Patient selection
The CONSORT diagram showing patient selection is presented in Figure 1.This multicenter retrospective study was conducted at eight institutions in Nagano Prefecture.A total of 263 NSCLC patients who received immune checkpoint inhibitors combined with platinum-based chemotherapy between December 2018 and January 2023 were initially included in the study database.Patients with NSCLC with epidermal growth factor receptor oncogenes, anaplastic lymphoma kinase rearrangement, and unknown PD-L1 expression were excluded from the analysis.Ultimately, 199 NSCLC patients were enrolled in the study, comprising 106 (53.3%) patients who experienced irAEs and 93 (46.7%) who did not.Data collection was concluded on April 30, 2023.All data were extracted from the electronic medical records of each participating institution.
Data collection methods and analyses were conducted in accordance with the principles outlined in the Declaration of Helsinki.The retrospective study protocol was reviewed and approved by the Research Ethics Committee of the Shinshu University School of Medicine (approval number: 5494).An opt-out approach was adopted, wherein the patients could decline participation by

Conclusion:
The study results suggest that high serum Alb is a predictive factor for irAE development and that the presence of multiple irAEs is a favorable prognostic indicator for NSCLC patients undergoing chemoimmunotherapy.

K E Y W O R D S
albumin, immune-related adverse event, non-small cell lung cancer, prognostic factor completing a form available on our institute's official website.Hence, the requirement for written informed consent was waived.

| Data collection
All patient data were retrospectively collected and assessed at the initiation of first-line treatment.The median follow-up time was 12.4 months.The median follow-up time in patients with irAEs and those without irAEs was 14.1 and 11.7 months, respectively.The best objective response to chemoimmunotherapy was assessed using the Response Evaluation Criteria in Solid Tumors, version 1.1. 21The OS was calculated from the date of chemoimmunotherapy initiation to the date of death or last followup visit.The objective response rate was defined as the sum of the complete response rate and partial response rate.Treatment efficacy assessments were conducted at the discretion of the attending physician.

| Statistical analysis
OS analyses were conducted using the Kaplan-Meier method with log-rank tests.Univariate and multivariate analyses were performed using logistic regression analysis to identify predictive factors for irAE development and Cox regression modeling to determine prognostic factors associated with OS.Variables deemed significant (p < 0.05) in the univariate analysis and clinically significant variables were included in the multivariate analysis.Statistical analysis was conducted using IBM SPSS Statistics, version 26.

| Prognostic factors associated with OS
Table 5 summarizes the prognostic factors associated with OS.The development of multiple irAEs (HR: 0.45, 95% CI: 0.24-0.86,p = 0.016), lower lactate dehydrogenase (LDH), and lower NLR were identified as independent favorable prognostic factors associated with OS.The irAE type was not a significant prognostic factor for OS (Table S1).

| DISCUSSION
This multicenter retrospective study revealed that high serum Alb level (≥3.5 g/dL) is a valuable predictive factor for the development of irAEs and that the development of multiple irAEs is a favorable prognostic factor for NSCLC patients undergoing chemoimmunotherapy.The mechanism underlying irAE development is multifaceted, including cellular immune pathway due to activation of autoreactive T cells, humoral immune pathway by autoantibody production, and inflammatory pathways resulting from overproduction of inflammatory cytokines. 22Serum Alb serves not only as an important indicator reflecting overall 'nutritional status but also plays a role in the activation of inflammatory cytokines.Elevated Alb level reduces prostaglandin E2 level, potentially facilitating the induction of inflammatory cytokines. 23revious research has reported high Alb level as a possible predictive factor for the development of irAEs.In a retrospective study of 200 patients with carcinomas, including NSCLC, gastric cancer, and malignant melanoma, high Alb level (≥3.5 g/dL) was reported to be a predictive factor for the development of irAEs and a favorable prognostic factor for OS. 24In our study, the incidence of irAEs was higher in NSCLC patients with high Alb level, although T A B L E 3 Type of multiple immune-related adverse events.high Alb level was not an independent favorable prognostic factor for OS.This discrepancy is probably due to the fact that not all irAEs correlate with survival outcomes.

Category
Our study found no significant difference in OS between patients with irAEs and those without irAE.Numerous studies have explored the correlation between individual irAEs and the prognosis of NSCLC patients undergoing immunotherapy.A previous meta-analysis reported an association between thyroid dysfunction and favorable prognosis for NSCLC patients undergoing immunotherapy. 25urthermore, a previous study reported dermatological adverse events as prognostic factors associated with survival outcomes in metastatic melanoma patients treated with anti-PD-1 antibody. 26However, the type of irAE that is a favorable prognostic factor may vary depending on cancer type and study population, necessitating further investigation.This study also suggests that the development of multiple irAEs, along with LDH levels (<223 U/L) and lower NLR (<3), independently correlate with favorable prognostic factor associated with OS.These findings regarding LDH and NLR as prognostic factors for NSCLC patients treated with immunotherapy are consistent with previous reports. 27,28Additionally, a retrospective study of 623 NSCLC patients treated with immunotherapy found that those experiencing multiple irAEs had significantly longer survival (progression-free survival/OS) than those without irAEs. 29The development of multiple irAEs may indicate increased activation of autoreactive T cells compared with a single irAE and a higher complication rate of irAEs, which is associated with a better prognosis.The incidence of skin lesions (irAE) correlates with the prognosis of patients with malignant melanoma treated with immunotherapy. 30In our study, the highest rate of skin rash (59.1%) may have contributed to the favorable prognosis factor for OS.No significant difference was observed in OS based on irAE severity.The median OS did not significantly differ among NSCLC patients with Grade 1-2 irAEs (p = 0.464) or Grade 3-4 irAEs (p = 0.936) and NSCLC patients without irAEs (Figure S1).This contrasts with a previous that reported a significant difference in OS for NSCLC patients treated with immunotherapy between those experiencing mild and severe irAEs (34.3 vs. 17.3 months, p = 0.021). 31Regarding this study, it is possible that with a longer follow-up period, OS differences could appear based on irAE severity.Thus, further follow-up and evaluation are warranted.
This study has several limitations.First, this study was retrospective in nature and had a small sample size.Moreover, treatment regimen selection and treatment efficacy assessment were at the discretion of the attending physician.Second, the study did not examine the time until the development of individual irAEs.Third, the follow-up period was insufficient to fully evaluate OS.Finally, the correlation between individual irAEs and survival time could not be examined.
In conclusion, high Alb level is a predictive factor for the development of irAEs, while the development of multiple irAEs is a favorable prognostic factor for NSCLC patients treated with chemoimmunotherapy.In the future, EGFR mutaƟon (N=31) NSCLC paƟents with ALK rearrangement (N=3) NSCLC paƟents with unknown PD-L1 expression (N=30) NSCLC paƟents without EGFR mutaƟons and ALK rearrangement who treated with immune checkpoint inhibitors combined with plaƟnum-based chemotherapy.(N=199) NSCLC paƟents with immune-related adverse events (irAEs) NSCLC paƟents without irAEs (N=106) (N=93)

T A B L E 2
Abbreviation: IrAE, immune-related adverse event.

F
I G U R E 2 Kaplan-Meier curves.(A) The median overall survival in the without-irAE group was not significantly different from that in the with-irAE group (23.3 vs. 25.3 months, HR 0.87 [0.56-1.35],p = 0.539).(B) The median overall survival in the without-irAE and single-irAE groups was significantly shorter than that in the multiple-irAE group (23.3 months vs. not reached, HR 0.54 (0.29-1.00), p = 0.049).irAE: immune-related adverse events, HR: hazard ratio.

Table 4
Patient characteristics.
summarizes the predictive factors associated with the development of irAEs.In the multivariate analysis, a T A B L E 1 out irAEs and those with a single irAE was significantly shorter than in those with multiple irAEs (23.1 months vs. not reached; HR: 0.54, 95% CI: 0.29-1.00,p = 0.049).NSCLC patients with multiple irAEs exhibited a high 2year OS rate of 71.6%, compared with 46.6% for patients without irAEs or with a single irAE.
Predictive factors associated with development of immune-related adverse events.